added negative tests in jest for the isProperFraction, tests pass

Author: marscancode

implement-and-rewrite-tests/rewrite-tests-with-jest/2-is-proper-fraction.test.js

@@ -21,3 +21,15 @@ test(`should return true when is a proper fraction`, () => {
 test(`should return true when numerator is 0`, () => {
   expect(isProperFraction(0, 1)).toEqual(true);
 });
+
+test(`proper fraction with a negative numerator but positive denominator`, () => {
+  expect(isProperFraction(-2, 3)).toEqual(true);
+});
+
+test(`proper fraction with a positive numerator but negative denominator`, () => {
+  expect(isProperFraction(2, -3)).toEqual(true);
+});
+
+test(`proper fraction with both a negative numerator and denominator`, () => {
+  expect(isProperFraction(-2, -3)).toEqual(true);
+});